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Patel JC, Sherpa AD, Melani R, Witkovsky P, Wiseman MR, O'Neill B, Aoki C, Tritsch NX, Rice ME. GABA co-released from striatal dopamine axons dampens phasic dopamine release through autoregulatory GABA A receptors. Cell Rep 2024; 43:113834. [PMID: 38431842 DOI: 10.1016/j.celrep.2024.113834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/29/2023] [Accepted: 02/05/2024] [Indexed: 03/05/2024] Open
Abstract
Striatal dopamine axons co-release dopamine and gamma-aminobutyric acid (GABA), using GABA provided by uptake via GABA transporter-1 (GAT1). Functions of GABA co-release are poorly understood. We asked whether co-released GABA autoinhibits dopamine release via axonal GABA type A receptors (GABAARs), complementing established inhibition by dopamine acting at axonal D2 autoreceptors. We show that dopamine axons express α3-GABAAR subunits in mouse striatum. Enhanced dopamine release evoked by single-pulse optical stimulation in striatal slices with GABAAR antagonism confirms that an endogenous GABA tone limits dopamine release. Strikingly, an additional inhibitory component is seen when multiple pulses are used to mimic phasic axonal activity, revealing the role of GABAAR-mediated autoinhibition of dopamine release. This autoregulation is lost in conditional GAT1-knockout mice lacking GABA co-release. Given the faster kinetics of ionotropic GABAARs than G-protein-coupled D2 autoreceptors, our data reveal a mechanism whereby co-released GABA acts as a first responder to dampen phasic-to-tonic dopamine signaling.
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Affiliation(s)
- Jyoti C Patel
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA.
| | - Ang D Sherpa
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA; Center for Neural Science New York University, 4 Washington Place, New York, NY 10003, USA
| | - Riccardo Melani
- NYU Neuroscience Institute, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Paul Witkovsky
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Madeline R Wiseman
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Brian O'Neill
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Chiye Aoki
- NYU Neuroscience Institute, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA; Center for Neural Science New York University, 4 Washington Place, New York, NY 10003, USA
| | - Nicolas X Tritsch
- NYU Neuroscience Institute, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Margaret E Rice
- Department of Neurosurgery, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA; NYU Neuroscience Institute, New York University Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA.
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Bilash OM, Actor-Engel HS, Sherpa AD, Chen YW, Aoki C. Suppression of food restriction-evoked hyperactivity in activity-based anorexia animal model through glutamate transporters GLT-1 at excitatory synapses in the hippocampus. Synapse 2021; 75:e22197. [PMID: 33619810 DOI: 10.1002/syn.22197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 12/22/2022]
Abstract
Severe voluntary food restriction is the defining symptom of anorexia nervosa (AN), but anxiety and excessive exercise are maladaptive symptoms that contribute significantly to the severity of AN and which individuals with AN have difficulty suppressing. We hypothesized that the excitability of hippocampal pyramidal neurons, known to contribute to anxiety, leads to the maladaptive behavior of excessive exercise. Conversely, since glutamate transporter GLT-1 dampens the excitability of hippocampal pyramidal neurons through the uptake of ambient glutamate and suppression of the GluN2B-subunit containing NMDA receptors (GluN2B-NMDARs), GLT-1 may contribute toward dampening excessive exercise. This hypothesis was tested using the mouse model of AN, called activity-based anorexia (ABA), whereby food restriction evokes the maladaptive behavior of excessive wheel running (food restriction-evoked running, FRER). We tested whether individual differences in ABA vulnerability of mice, quantified based on FRER, correlated with individual differences in the levels of GLT-1 at excitatory synapses of the hippocampus. Electron microscopic immunocytochemistry (EM-ICC) was used to quantify GLT-1 levels at the excitatory synapses of the hippocampus. The FRER seen in individual mice varied more than 10-fold, and Pearson correlation analyses revealed a strong negative correlation (p = .02) between FRER and GLT-1 levels at the axon terminals of excitatory synapses and at the surrounding astrocytic plasma membranes. Moreover, synaptic levels of GluN2B-NMDARs correlated strongly with GLT-1 levels at perisynaptic astrocytic plasma membranes. There is at present no accepted pharmacotherapy for AN, and little is known about the etiology of this deadly illness. Current findings suggest that drugs increasing GLT-1 expression may reduce AN severity through the reduction of GluN2B-NMDAR activity.
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Affiliation(s)
- Olesia M Bilash
- The Neuroscience Institute, NYU Langone Medical Center, New York, NY, USA.,Center for Neural Science, New York University, New York, NY, USA
| | | | - Ang D Sherpa
- Center for Neural Science, New York University, New York, NY, USA
| | - Yi-Wen Chen
- Center for Neural Science, New York University, New York, NY, USA
| | - Chiye Aoki
- The Neuroscience Institute, NYU Langone Medical Center, New York, NY, USA.,Center for Neural Science, New York University, New York, NY, USA
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Aoki C, Sherpa AD. Making of a Synapse: Recurrent Roles of Drebrin A at Excitatory Synapses Throughout Life. Advances in Experimental Medicine and Biology 2017; 1006:119-139. [DOI: 10.1007/978-4-431-56550-5_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Odackal J, Sherpa AD, Patel N, Colbourn R, Hrabetova S. T-type calcium channels contribute to calcium disturbances in brain during hyponatremia. Exp Neurol 2015; 273:105-13. [PMID: 26257025 PMCID: PMC4644432 DOI: 10.1016/j.expneurol.2015.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 07/21/2015] [Accepted: 08/04/2015] [Indexed: 11/26/2022]
Abstract
Disturbance of calcium homeostasis is implicated in the normal process of aging and brain pathology prevalent in the elderly such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis. Previous studies demonstrated that applying a hyponatremic iso-osmotic (low-NaCl) artificial cerebrospinal fluid (ACSF) to rodent hippocampus causes extracellular calcium to rapidly decrease. Restoring normonatremia after low-NaCl treatment causes a rapid increase in extracellular calcium that overshoots baseline. This study examined the amplitude, timing, and mechanism of these surprising calcium changes. We also tested whether hyponatremia increased calcium entry into brain cells or calcium binding to chondroitin sulfate (CS), a negatively charged constituent of the extracellular matrix (ECM) that may be occupied by sodium during normonatremia. We report three major findings. First we show that CS does not contribute to extracellular calcium changes during low-NaCl treatments. Second, we show that the time to minimum extracellular calcium during low-NaCl treatment is significantly shorter than the time to maximum extracellular calcium in recovery from low-NaCl treatment. Third, we show that the decrease in extracellular calcium observed during hyponatremia is attenuated by ML 218, a highly selective T-type calcium channel blocker. Together these data suggest that calcium rapidly enters cells at the onset of low-NaCl treatment and is extruded from cells when normonatremia is restored. Calcium binding to CS does not significantly contribute to calcium changes in brain during hyponatremia. Differences in timing suggest that extracellular calcium changes during and in recovery from hyponatremia occur by distinct mechanisms or by a multistep process. Finally, partial block of extracellular calcium influx by ML 218 suggests that T-type channels are involved in calcium entering cells during hyponatremia. Given the high prevalence of hyponatremia among elderly patients and the growing understanding of calcium's role in multiple neurologic pathologies, this study promotes a novel approach for studying and potentially preventing the effects of hyponatremia on calcium dysregulation in brain tissue.
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Affiliation(s)
- John Odackal
- College of Medicine, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
| | - Ang D Sherpa
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA; Neural and Behavioral Science Graduate Program, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA
| | - Nisha Patel
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA
| | - Robert Colbourn
- College of Medicine, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA; Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA; School of Graduate Studies, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA
| | - Sabina Hrabetova
- Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA; The Robert Furchgott Center for Neural and Behavioral Science, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA
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